Aerosol antimicrobial compositions

ABSTRACT

An aerosol antimicrobial composition is provided with the following ingredients: a) an anionic polymer or prepolymer; (b) a quaternary ammonium compound, the components (a) and (b) combining to form an antimicrobially effective complex; (c) at least one water-soluble or dispersible organic solvent having a vapor pressure of at least 0.001 mm Hg at 25° C., said at least one organic solvent present in a solubilizing—or dispersion—effective amount; (d) an effective amount of a propellant; and (e) the remainder, water. Further is provided a novel method of decontaminating a surface fouled with microorganisms and a dispenser for said aerosol composition. The novel composition advantageously has both disinfectancy (contact efficacy) and residual antimicrobial efficacy.

RELATED APPLICATIONS

This is a Continuation-in-Part of Ser. No. 09/116,190, filed Jul. 15,1998, now U.S. Pat. No. 6,080,387.

FIELD OF THE INVENTION

The present invention relates generally to dispensable antimicrobialcompositions, and more particularly to an aerosol composition which hasboth disinfectancy (contact efficacy) and residual antimicrobialefficacy.

BACKGROUND OF THE INVENTION

In the seemingly perpetual battle against infection by pathogenicmicroorganisms, a recent, alarming trend has been observed. Antibioticmedications and treatments long thought to have conquered, if notarrested, the invasive infection of humans by such pathogens (generally,prokaryotic organisms, such as bacteria), have recently begun to fail orlose effectiveness at stopping such infections. Terrifying, andseemingly increasingly frequent, news stories of either fatal or seriousinfection by such bacteria as the common intestinal inhabitantEscherichia coli 0.157 (especially affecting small children and thosewith a lesser, or challenged immune system), and by certain species ofStaphylococcus sp. (colorfully, but somewhat inaccurately dubbed in newsaccounts as “flesh eating bacteria”) have led to the conclusion thatprevention, by decontamination of surfaces touched by humans, may indeedbe a wiser remedy than cure by antibiotics. So, the search forappropriate antimicrobial treatments of surfaces is spurred by this newchallenge by these old enemies of the human population.

The use of quaternary ammonium compounds as antimicrobial agents is wellknown in the art. See U.S. Pat. Nos. 2,746,928, 3,344,018, 3,719,711,and JP 01/046081. For instance, quaternary ammonium compounds have beenincorporated into polymer and liquid compositions to protect thecompositions themselves from microbial attack (i.e., used aspreservatives). See U.S. Pat. Nos. 3,471,423, 5,028,619 and 5,399,343.Furthermore, quaternary ammonium compounds have also been employed as anadditive in a variety of household products including detergents. SeeU.S. Pat. Nos. 3,093,591, 3,560,390, 4,272,395 and 4,576,729.

An effort to remedy the issues faced by prior antimicrobial compositionswas posed in the commonly owned Zhou et al., S. U.S. Pat. No. 6,017,561,the disclosure of which is incorporated herein by reference. This PatentApplication contemplated the formation of a novel mixed anionic/cationicpolymer having residual antimicrobial efficacy. However, the applicationdid not disclose, suggest or teach that an aerosol compositioncontaining a mixture of an anionic polymer and a quaternary ammoniumcompound has both disinfectancy (contact efficacy) and residualantimicrobial efficacy. There are also various compositions, especiallyhard surface cleaners, which have been delivered as aerosols but whichdo not contain the inventive mixture of an anionic polymer and aquaternary ammonium compound having both disinfectancy (contactefficacy) and residual antimicrobial efficacy.

SUMMARY OF THE INVENTION

The invention is an antimicrobial dispensable composition comprising:

(a) an anionic polymer or prepolymer;

(b) a quaternary ammonium compound, the components (a) and (b) combiningto form an antimicrobially effective complex;

(c) at least one water-soluble or dispersible organic solvent having avapor pressure of at least 0.001 mm Hg at 25° C., said at least oneorganic solvent present in a solubilizing—or dispersion—effectiveamount;

(d) an effective amount of a propellant; and

(e) the remainder, water.

In one aspect, the invention is directed to a dispensable compositionfor treating surfaces which contain microorganisms.

In another aspect, the invention is directed to a method fordecontaminating a surface containing microorganisms by contacting thesurface with the dispensable composition.

In a further aspect, the invention is directed to a device, fordispensing a composition for treating a surface containingmicroorganisms, which includes, a pressurized closed containercontaining the above antimicrobial composition and nozzle means forreleasing said composition towards a contaminated surface.

It is therefore an object and an advantage of the present invention toprovide antimicrobial composition which has both disinfectancy (contactefficacy) and residual antimicrobial efficacy.

It is another object and another advantage of the present invention toprovide a convenient and easy to use product which has prolongedresidual efficacy in a single treatment of surfaces, which thus reduceslabor, time, effort and cost to treat such surfaces.

It is a further object and advantage of the present invention to providea method for decontaminating a surface containing microorganisms, orwhich can be potentially contaminated thereafter.

It is a still further object and advantage of this invention to providea dispensable antimicrobial composition which contacts a surface andforms thereon a film or residue which has prolonged antimicrobialefficacy.

It is yet another object and advantage of this invention to provide adispensable antimicrobial composition which has up to 99.9% residualefficacy in a 24 hour period.

It is a final object and advantage of this invention to provide adispensable antimicrobial composition which out performs commerciallyavailable products which claim to have antimicrobial efficacy.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides an aerosol formulation comprising a novelantimicrobial composition for treating one or more surfaces containingmicroorganisms. These surfaces include those which are typicallycontacted by human touch: bathroom surfaces, such as a bath tub, sink,commode, toilet, or shower stall, which may have glass doors, andinclude vertical wall surfaces typically made of tile, glass, orcomposite materials; kitchen surfaces, such as countertops, stove tops,sinks, table tops, chairs; and generally, any other surface, whetherhard or soft, such as furniture, window ledges, window frames and otheredges, door knobs, handles, tools, appliances, utility devices (such astelephone handsets and portable telephones), implements (such as pens,mechanical pencils and the like), wrist watches, clothing (such asstockings), shoes, outer garments, and other common and uncommonsurfaces. Each of these types of surfaces can act to harbormicroorganisms, including bacteria, fungi, molds, mildew and viruses.Thus, each such surface can communicate a potential infectious vector tothe unwitting person (or, in the case of cross-species infection,household pets) unless treated with an appropriate antimicrobialcomposition. The inventive antimicrobial composition is intended to sotreat and decontaminate such surfaces, and others, by aerosolapplication of a metered discrete amount of the composition via adispenser onto the surface to be treated. The antimicrobial compositionis generally merely applied as an aerosol composition to the surface inorder to effect antimicrobial efficacy. The surface can additionally bespread or wiped, but this would then remove the composition and maylessen the efficacy thereof.

The antimicrobial composition is formulated with ingredients whichthemselves are found often in cleaners, such as hard surface and fabriccleaners. Thus, an additional benefit of the composition is that it canalso act as a cleaner and soil remover. It is preferred that thisbenefit be achieved without detriment to its primary advantage as anantimicrobial composition.

The aerosol formulation comprises an antimicrobial composition that ismixed with a propellant. The composition has the following ingredients:

(a) an anionic polymer or prepolymer;

(b) a quaternary ammonium compound, the components (a) and (b) combiningto form an antimicrobially effective complex;

(c) at least one water-soluble or dispersible organic solvent having avapor pressure of at least 0.001 mm Hg at 25° C., said at least oneorganic solvent present in a solubilizing—or dispersion—effectiveamount;

(d) an effective amount of a propellant; and

(e) the remainder, water.

Additional adjuncts in small amounts such as buffers, fragrances, dyesand the like can be included to provide desirable attributes of suchadjuncts.

In the application, effective amounts are generally those amounts listedas the ranges or levels of ingredients in the descriptions which followhereto. Unless otherwise stated, amounts listed in percentage (“%'s”)are in weight percent (based on 100% active) of the cleaningcomposition.

1. Anionic Polymer or Prepolymer

The anionic polymer or prepolymer (generally, component) generally hasan acid number greater than 10. It is an essential part of the inventionsince it combines with the quaternary ammonium compound in a mechanismwhich, as yet, is not completely understood, and may or may not involvean ionic bonding, or pairing, mechanism. The anionic component isusually a polymer having an average molecular weight of about 100 toabout 2,000,000 daltons, with an acid number preferably greater thanabout 10. As used herein, “acid number” retains its conventional meaningand is determined by the number of milligrams of potassium hydroxiderequired for the neutralization of the corresponding acids of theanionic groups present in one gram of the polymer.

In the antimicrobial composition, the anionic component may or may notbe partially or completely neutralized by the quaternary ammoniumcompound to form a polymer complex. The actual manner of combining ofthe two key components of the inventive antimicrobial compositions hasnot been fully determined at this time. Thus, instead of ionic bonding ,as in the classic sense of anionic and cationic materials forming an ionpair (See Cationic Surfactants, Physical Chemistry, in: SurfactantScience Series Vol. 37, p. 93 (Marcel Dekker, 1983)), when the liquid,dispensable compositions of this invention are delivered from thedispenser to a surface, physical association may actually be takingplace, such as occlusion, where the quaternary ammonium compound isevenly dispersed in the resulting polymer matrix or film. It is alsospeculated that, in the dispenser, the components may also form anotherstate in which ion pairing does take place. However, all of theforegoing is by way of non-binding theory.

The antimicrobial composition is preferably prepared by mixing effectiveamounts of the anionic component and the quaternary ammonium compound inwater with agitation. A water miscible solvent and/ordispersing/emulsifying/wetting agent is preferably added before the twomain. components are mixed together. The “dispersing/emulsifying/wettingagent” comprises any suitable agent which will cause the admixture ofanionic component and the quaternary ammonium compound to be stablydistributed substantially homogeneously in the liquid composition.Depending on the particular anionic components and quaternary ammoniumcompounds used to make the composition, the presence of cross-linkers,stabilizers and other variables, the antimicrobial compositions of theinvention may exist as emulsions, suspensions, dispersions, solutions,or possibly, as other forms of liquids, such as microemulsions andliquid crystals.

The anionic component, which can be a polymer or prepolymer, ispreferably derived from monomers having anionic groups attached thereto.Preferably, the polymer has an average molecular weight of about 200 to2,000,000, more preferably, about 2,000 to 1,000,000, and mostpreferably, about 5,000 to 150,000 daltons, with an acid number greaterthan about 10 and preferably from about 60 to 700.

Preferred anionic polymers are selected from the group consisting of:(1) a homopolymer that is selected from the group consisting of vinylsulfonates, acrylates, methacrylates, styrene sulfonates, maleates,vinyl sulfates and mixtures thereof; (2) a copolymer that is derivedfrom (i) one or more anionic monomers selected from the group consistingof vinyl sulfonates, acrylates, methacrylates, styrene sulfonates,maleates, vinyl sulfates; and (ii) one or more nonionic monomersselected from vinyl esters, vinyl alcohols, vinyl ethers, acrylamides,methacrylamides, alkyl or aryl acrylates, alkyl or aryl methacrylates,alkyl or aryl maleates, acrylonitriles, vinyl pyrrolidones, alkenes,such as, for example, styrene, ethylene and propylene, multifunctionalacids, polyols, multifunctional amines, multifunctional isocyanates andmultifunctional epoxy compounds; and (3) methylcarboxycellulose.

As is apparent, copolymers may include nonionic monomers. A preferredcopolymer comprising nonionic and anionic monomers is formed fromacrylic acid esters, such as methacrylate or acrylate. The anionicpolymers can be in their salt, acid, or partially protonated forms.

The solubility/dispersability of the polymer will depend, in part, onits molecular weight, acid number, and the solvent and/orwetting/dispersing/emulsifying agent involved. Optionally, the anionicpolymer or component may be cross-linked with common cross-linkers suchas, for example, carbodimide, aziridine, polyols, glyoxal, epoxycompounds, transition metal ions, and ionene polymers to reducesolubility. Typically, in formulating a liquid, dispensableantimicrobial composition, the anionic polymer is present in an amountof about 0.01 to 15%, more preferably about 0.1 to 10$, and mostpreferably, about 0.5 to 5% by weight of the composition. Importantexamples of the preferred anionic polymers include the acrylatecopolymers produced by B.F. Goodrich under the trademark Carboset.Preferred is Carboset GA 2123, which appears to be an acrylicacid/acrylate ester copolymer. Especially preferred are two differentcopolymers, namely, Omnirez 2000, which is a monoethylester ofpoly(methylvinylether/maleic) acid, from ISP, and Dermacryl 79, which isan acrylate/octylacrylamide copolymer, from National Starch. Theseparticular latter copolymers resulted in optimal films in the inventivecompositions hereof. There further appears to be a preferential ratio ofthe anionic component to the quaternary ammonium compound. This ratiomay be from about 1:100 to about 100:1, more preferably about 1:10 toabout 10:1, and most preferably, about 5:1 to about 1:5. In balancingthe ratio of anionic component to quaternary ammonium compound, one mustkeep in mind the desirable characteristics in the dispenser (i.e., “canstability”) versus that of the dispensed liquid versus that of the curedor dried film/residue (when the liquids/solvents volatilize or “flashoff”). The more anionic polymer, the smoother, glassier appearing of theresulting film, and the more water soluble. The more quaternary ammoniumcompound, the less water soluble the resulting film, but, aesthetics ofthe film appear to become less pleasing, however, such less attractiveforms are still part of the invention. The most preferred range of 5:1to 1:5 appears to result in an aesthetically pleasing film which hasexcellent residual antimicrobial efficacy, as well as disinfectancy.This also seems to imply that, in the cured film/residue, there mayactually not be complete ion pairing between the quaternary ammoniumcompound and the anionic sites in the anionic polymer, since thequaternary ammonium active sites are available for residual microbialkill, although there is clearly an interaction between the twocomponents. Again, the mechanism of the film/residue is not completelyunderstood, so these latter observations are made by way of non-bindingtheory. Further, it is preferred to obtain a transparent to translucent,smooth, homogeneous, tack-free film. So, other additives can be added toimprove the film's characteristics, such as the use of various watersoluble polymers, and by neutralizing some of the acid groups of theanionic polymers by various buffers, such as alkali metal (Na⁺, K⁺) andammonium buffers, although organic buffers, such as alkanolamines may beused. Additionally, some wetting/dispersing/emulsifying agents asdescribed below in 4. help to enable the formation of effective films orresidues, by placing the ingredients into dispersion. By “effective” ismeant that the films achieve consistent residual efficacy throughout thefilm.

2. Quaternary Ammonium Compound

A critical second component of the invention is a quaternary ammoniumcompound, or surfactant. These types of surfactants are typically usedin bathroom cleaners because they are generally considered “broadspectrum” antimicrobial compounds, having efficacy against both grampositive (e.g., Staphylococcus so) and gram negative (e.g., Escherichiacoli or Klebsiella s) microorganisms. Thus, the quaternary ammoniumsurfactant, or compounds, are incorporated forbacteriostatic/disinfectant purposes and should be present in amountseffective for such purposes.

The quaternary ammonium compounds are selected from mono-long-chain,tri-short-chain, tetraalkyl ammonium compounds, di-long-chain,di-short-chain tetraalkyl ammonium compounds, trialkyl, mono-benzylammonium compounds, and mixtures thereof. By “long” chain is meant aboutC₆₋₃₀ alkyl. By “short” chain is meant about C₁₋₅ alkyl, preferablyC₁₋₃. Suitable counterions for such quaternary ammonium compoundsinclude halides (chlorides, bromides, iodides), hydroxides,saccharinates, carbonates, phosphates, phosphonates, sulfates,bisulfates, alkylsulfates, carboxylates, other negatively chargedcounterions, and mixtures thereof. Preferred materials include the BTC885—which comprises a mixture of C₁₂₋₁₆ alkyl dimethylbenzyl ammoniumchloride, C₈/C₁₀ alkyl dimethyl ammonium chloride, di-C₈ alkyl dimethylammonium chloride, and di-C₁₀ alkyl dimethyl ammonium chloride—and 2125series from Stepan, which comprises di-C₂₄-dialkyl ammonium chloride,and the Barquat and Bardac series, such as Bardac MB 2050, from LonzaChemical. Also preferred appears to be a mixed quaternary ammoniumsurfactant in which there is a combination of di-long-chain,di-short-chain tetraalkyl ammonium compounds, and trialkyl, mono-benzylammonium compounds. Most preferred appears to be quaternary ammoniumcompounds (or “quats”) which contain either chloride or saccharinatecounterions, or, especially, a mixture thereof. The saccharinate quat isOnyxide 3300, from Stepan Company. Both the chloride quats and thesaccharinate quats when combined, provide excellent residualantimicrobial kill performance (referred to herein as “99.99%Efficacy”). The ratio of these counterions should be 1:100 to 100:1,most preferably 1:10 to 10:1. These particularly preferred quaternaryammonium surfactants form both smooth films with the anionic polymerslisted above, but also are the most effective at broad spectrum contactand residual antimicrobial efficacy (both gram negative and grampositive microorganisms), antifungal and antiviral efficacy. Typicalamounts of the quaternary ammonium compound range from preferably about0.01-5%, more preferably about 0.01-2%.

3. Solvents

The solvent is a water soluble or dispersible organic solvent having avapor pressure of at least 0.001 mm Hg at 25° C. It is preferablyselected from C₁₋₆ alkanols, C₁₋₆ diols, C₁₋₆ alkyl ethers of alkyleneglycols and polyalkylene glycols, and mixtures thereof. The alkanol canbe selected from methanol, ethanol, n-propanol, “isopropanol,” thevarious positional isomers of butanol, pentanol, and hexanol, andmixtures of the foregoing. It may also be possible to utilize inaddition to, or in place of, said alkanols, the diols such as methylene,ethylene, propylene and butylene glycols, and mixtures thereof, andincluding polyalkylene glycols.

It is preferred to use a C₁₋₄ alkanol solvent in this invention. Onepreferred alkanol is ethanol, which advantageously acts as both asolvent, to maintain the ingredients in the liquid composition indispersion, as well as a disinfectant. If mixtures of solvents are used,the amounts and ratios of such solvents used are important to determinethe optimum performances of the inventive composition. One furtherpreferred solvent which may be either added in addition to ethanol or inplace thereof is ethylene glycol. It is preferred to have the totalamount of solvent to at least 20%, more preferably least 30%, and mostpreferably, at least 50%, of the composition. A preferred range is about20-99.9%. These amounts of solvents are generally referred to asdispersion effective or solubilizing effective amounts, since the othercomponents, such as surfactants, are materials which are assisted intosolution by the solvents. As in the case of ethanol, the solvent canalso have disinfectancy capacity itself. Finally, the solvent is alsoimportant as a cleaning materials itself, helping to loosen andsolubilize certain soils for easy removal from the surface treated.

4. Wetting/Emulsifying/Dispersing Agent

The wetting/emulsifying/dispersing agent may be preferably a surfactant(preferably, anionic, cationic nonionic, amphoteric, or zwitterionicsurfactant; but the quaternary ammonium surfactant of 2., above, is notconsidered as one of the wetting agents herein), or possibly, ahydrotrope (which is also treated below, in 5.). The surfactant may bean nonionic, amphoteric or zwitterionic surfactant, or mixtures thereof.The following is a nonlimiting description of surfactants which might beemployed in the present invention. The description is intended toexemplify that a wide variety of surfactants can be used according tothe present invention.

a. Anionic, Nonionic, Amphoteric and Zwitterionic Surfactants

The anionic surfactants may include a negatively charged watersolubilizing group.

The nonionic surfactants may be selected from modified polysiloxanes,alkoxylated alcohols, alkoxylated phenol ethers, glycosides, and thelike. Trialkyl amine oxides, and other surfactants often referred to as“semi-polar” nonionics, may also be employed.

Most preferred are modified polysiloxanes. The modified polysiloxane canbe an alkoxylated dimethylsiloxane, such as those available from BykChemie, such as BYK-345 and Dow Corning 5103 and Q2-5247, both from DowCorning.

The alkoxylated alcohols may include, for example, ethoxylated, andethoxylated and propoxylated C₆₋₁₆ alcohols, with about 2-10 moles ofethylene oxide, or 1-10 and 1-10 moles of ethylene and propylene oxideper mole of alcohol, respectively. Exemplary surfactants are availablefrom Shell Chemical under the trademarks Neodol and Alfonic, and fromHuntsman Chemicals under the trademark Surfonic (e.g., Surfonic L12-6, aC₁₀₋₁₂ ethoxylated alcohol with 6 moles of ethylene oxide, and SurfonicL12-8, a C₁₀₋₁₂ ethoxylated alcohol with 8 moles of ethylene oxide).

The alkoxylated phenol ethers may include, for example, octyl- andnonylphenol ethers, with varying degrees of alkoxylation, such as 1-10moles of ethylene oxide per mole of phenol. The alkyl group may vary,for example, from C₆₋₁₆, with octyl- and nonyl chain lengths beingreadily available. Various suitable products are available from Rohm &Haas under the trademark Triton, such as Triton N-57, N-101, N-111, X45,X-100, X-102, from Mazer Chemicals under the trademark Macol, from GAFCorporation under the trademark Igepal, and from Huntsman under thetrademark Surfonic.

The glycosides, particularly the alkyl polyglycosides, may also be usedas a surfactant for purposes of the aerosol formulation of the presentinvention. These glycosides include those of the formula:

RO(C_(n)H_(2n)O)_(y)(Z)_(x)

wherein R is a hydrophobic group (e.g., alkyl, aryl, alkylaryl etc.,including branched or unbranched, saturated and unsaturated, andhydroxylated or alkoxylated members of the foregoing, among otherpossibilities) containing from about 6 to about 30 carbon atoms,preferably from about 8 to about 15 carbon atoms, and more preferablyfrom about 9 to about 13 carbon atoms; n is a number from 2 to about 4,preferably 2 (thereby giving corresponding units such as ethylene,propylene and butylene oxide); y is a number having an average value offrom 0 to about 12, preferably 0; Z is a moiety derived from a reducingsaccharide containing 5 or 6 carbon atoms (e.g., a glucose, fructose,mannose, galactose, talose, gulose, allose, altrose, idose, arabinose,xylose, lyxose, or ribose unit, etc., but most preferably a glucoseunit); and x is a number having an average value of from 1 to about 10,preferably from 1 to about 5, and more preferably from 1 to about 3.

It would be apparent that a number of variations with respect to themakeup of the glycosides are possible. For example, mixtures ofsaccharide moieties (Z) may be incorporated into polyglycosides. Also,the hydrophobic group (R) can be attached at the 2-, 3-, or 4-positionsof a saccharide moiety rather than at the 1-position (thus giving, forexample, a glucosyl as opposed to a glucoside). In addition, normallyfree hydroxyl groups of the saccharide moiety may be alkoxylated orpolyalkoxylated. Further, the (C_(n)H_(2n)O)_(y) group may includeethylene oxide and propylene oxide in random or block combinations,among a number of other possible variations.

An exemplary glycoside surfactant is APG 325n, which is manufactured bythe Henkel Corporation. APG 325n is a nonionic alkyl polyglycoside inwhich R is a mixture of C₉, C₁₀ and C₁₁ chains in a weight ratiorespectively of 20:40:40 (equivalent to an average of C_(10.2)), with xof 1.6, and an HLB of 13.1.

Compositions containing other surfactants, such as some amine oxides,may be less compatible with the tin-plated steel can environment (oreven with steel cans that are lined with, e.g., an epoxy phenoliccoating). Tin-plated steel cans are desirable as containers for aerosolcompositions because they are more readily available and are lessexpensive than aluminum or specially lined steel cans.

The amine oxides, referred to as mono-long chain, di-short chain,trialkyl amine oxides, have the general configuration:

wherein R¹ is C₆₋₂₄ alkyl, and R² and R³ are both C₁₋₄ alkyl, or C₁₋₄hydroxyalkyl, although R² and R³ do not have to be equal. These amineoxides can also be ethoxylated or propoxylated. The preferred amineoxide is lauryl amine oxide. The commercial sources for such amineoxides are Barlox 10, 12, 14 and 16 from Lonza Chemical Company, Varoxby Witco and Ammonyx by Stepan Company.

A further semi-polar nonionic surfactant isalkylamidoalkylenedialkyl-amine oxide. Its structure is shown below:

wherein R¹ is C₅₋₂₀ alkyl, R² and R³ are C₁₋₄ alkyl,

although R² and R³ do not have to be equal or the same substituent, andn is 1-5, preferably 3, and p is 1-6, preferably 2-3. Additionally, thesurfactant could be ethoxylated (1-10 moles of EO/mole) or propoxylated(1-10 moles of PO/mole). This surfactant is available from varioussources as a cocoamidopropyldimethyl amine oxide; it is sold by LonzaChemical Company under the brand name Barlox C. Additional semi-polarsurfactants may include phosphine oxides and sulfoxides.

A preferred cationic surfactant is morpholinium ethosulfate, such asForestall (Atlas) G-271.

The amphoteric surfactant is typically an alkylbetaine, an amidobetaine,or a sulfobetaine. One group of preferred amphoterics arealkylamidoalkyl-dialkylbetaines. These have the structure:

wherein R¹ is C₆₋₂₀ alkyl, R² and R³ are both C₄ alkyl, although R² andR³ do not have to be equal, and m can be 1-5, preferably 3, and n can be1-5, preferably 1. These alkylbetaines can also be ethoxylated orpropoxylated. The preferred amidobetaine is cocoamidopropyldimethylbetaine, available from Lonza Chemical Co. as Lonzaine CO. Other vendorsare Henkel KGaA, which provides Velvetex AB, and Witco Chemical Co.,which offers Rewoteric AMB-15, both of which products are cocobetaines.

Potentially suitable zwitterionic surfactants can be found described inJones, U.S. Pat. No. 4,005,029, at columns 11-15, which are incorporatedherein by reference.

The amounts of surfactants present are to be somewhat minimized, forpurposes of cost-savings and to generally restrict the dissolved activeswhich could contribute to leaving behind residues when the aerosol isapplied to a surface. However, the amounts added are generally about0.001-5%, more preferably 0.002-3.00% surfactant. These are generallyconsidered to be dispersion-effective amounts.

5. Water and Miscellaneous

Since the composition is an aqueous composition, water can be, alongwith the solvent, be a predominant ingredient. The water should bepresent at a level of less than 70%, more preferably less than about65%, and most preferably, less than about 50%. Deionized water ispreferred.

Small amounts of adjuncts can be added for improving performance,stability or aesthetic qualities of the composition. For example,buffers can be added to maintain a constant pH (which for the inventionis between about 5-14, more preferably between about 8-13; formulationscontaining the tripotassiui and/or triammonium salts will naturally beat a lower end of the range as compared to the corresponding tetrasalts). These buffers include, for example, NaOH, KOH, Na₂CO₃, and K₂CO₃as alkaline buffers, and phosphoric, hydrochloric, sulfuric, and citricacids as acidic buffers, among others. It may be desirable to addchelating agents, such as polycarboxylates (e.g., EDTA and its alkalimetal and ammonium salts, especially K₄EDTA, see commonly assignedRobbins et al., U.S. Pat. No. 5,972,876, which is incorporated herein byreference), aminopolyphosphonates, and polyphosphonates, metasilicatesand organic amines. Chelating agents may help to potentiateantimicrobial efficacy or have other functional uses.

Further solubilizing materials, such as hydrotropes (e.g., water solublesalts of low molecular weight organic acids such as the sodium orpotassium salts of cumene-, toluene-, benzene-, and xylene sulfonicacid), may also be desirable. Adjuncts for cleaning include additionalsurfactants, such as those described in Kirk-Othmer, Encyclopedia ofChemical Technology, 3rd Ed., Volume 22, pp. 332-432 (Marcel-Dekker,1983), and McCutcheon's Soaps and Detergents (N. Amer. 1984), which areincorporated herein by reference. Aesthetic adjuncts include fragrancesor perfumes, such as those available from Givaudan, IFF, Quest, Sozio,Firmenich, Dragoco and others, and dyes or colorants which can besolubilized or suspended in the formulation, such asdiaminoanthraquinones. Enhancing ingredients, such as nerolidol, may bepresent to perform in multiple capacities, both aesthetic andfinctional, the composition (See commonly owned U.S. patent applicationSer. No. 09/085,340, of Blum et al., filed May 27, 1998, andincorporated herein by reference). Water-insoluble solvents maysometimes be desirable as added grease-or oily soil-cutting agents.These types of solvents include tertiary alcohols, hydrocarbons (e.g.,alkanes), pine-oil, d-limonene and other terpenes and terpenederivatives, and benzyl alcohols. Thickeners, such as calcium carbonate,sodium bicarbonate, aluminum oxide, and polymers, such as polyacrylate,starch, xanthan gum, alginates, guar gum, cellulose, and the like, maybe desired additives, although care must be taken since the inventivecompositions are meant to be relatively thin liquids for effectivedispensation from a pressurized canister. The use of some of thesethickeners (e.g., CaCO₃ or NaHCO₃) is to be distinguished from theirpotential use as builders, generally by particle size or amount used.Additional additives may include further antimicrobial compounds, suchas phenols (See, Moseman, U.S. Pat. No. 4,985,945, incorporated hereinby reference), pine oil (See Spaulding et al., U.S. Pat. No. 4,867,898,incorporated herein by reference) and liposome-like microemulsions suchas mentioned in the paper by T. Hamouda et al., “Microbiocidal Effectsof Liposomes-Like Microemulsions on Pathogenic Gram Negative Bacteria,”in: Poster Session 251/A Antimicrobial Therapy and Charactertization ofPathogens, American Society of Microbiology 98th Annual Meeting, May17-21, 1998, p. 152, said paper incorporated herein by reference.

As already noted above, the preferred container for dispensing of thepresent composition in aerosol form is a tin-plated steel can, but otheraerosol packages may be suitable for use. Therefore, it is advantageousto add one or more corrosion inhibitors to prevent or at least reducethe rate of expected corrosion of such a metallic dispenser. Chloridesalts, if present, may cause corrosion. Preferred corrosion inhibitorsinclude, for example, sodium nitrite, potassium nitrite, sodiumbenzoate, potassium benzoate, amine neutralized alkyl acid phosphatesand nitroalkanes, amine neutralized alkyl acid phosphates and volatileamines, diethanolamides, amine borates, hydroxylamines, alkanolamines,amine carboxylates, esters, volatile silicones, amines and mixturesthereof. Specific inhibitors include, for example, sodium lauroylsarcosinate, available from Stepan Company under the trademark Maprosyl30, sodium meta silicate, sodium or potassium benzoate, triethanolamine,and morpholine. When employed, the corrosion inhibitor preferablycomprises about 0.01% to 5% of the aerosol formulation.

6. Propellant

The antimicrobial composition is delivered in the form of an aerosol.The propellant comprises, for example, a hydrocarbon, of from 1 to 10carbon atoms, such as methane, ethane, n-propane, n-butane, isobutane,n-pentane, isopentane, and mixtures thereof. The propellant may also beselected from halogenated hydrocarbons including, for example,fluorocarbons, chlorocarbons, chlorofluorocarbons, and mixtures thereof.(Besides of concerns about the destruction of the stratosphere's ozonelayer, the use of fluorocarbons and chlorofluorocarbons is lesspreferred.) Examples of other suitable propellants are found in P. A.Sanders Handbook of Aerosol Technology (Van Nostrand Reinhold Co.)(1979) 2nd Ed., pgs. 348-353 and 364-367, which are incorporated byreference herein. Further, non-hydrocarbon propellants may be possible,such as carbon dioxide, nitrogen, compressed air, and, possibly, denseor supercritical fluids.

A liquefied gas propellant mixture comprising about 85% isobutane and15% propane is preferred because it provides sufficient pressure toexpel the cleaning composition from the container and provides goodcontrol over the nature of the spray upon discharge of the aerosolformulation. Preferably, the propellants comprises about 1% to 50%, morepreferably about 2% to 25%, and most preferably about 5% to 15% of theaerosol formulation.

The aerosol formulation is preferably stored in and dispensed from apressurized can that is equipped with a nozzle so that an aerosol of theformulation can be readily sprayed onto a surface. Dispensers are knownin the art and are described, for example, in U.S. Pat. Nos. 4,780,100,4,652,389, and 3,541,581 which are incorporated by reference herein.Although pressure within the dispenser, i.e., can pressure, does notappear to be critical, it may be preferred to range from about 10 to 100psiq. at 70° F. (21.1° C.).

In loading the dispenser, the non-propellant components of the aerosolformulation are mixed into a concentrate and loaded into the dispenserfirst. Thereafter, the liquefied gaseous propellant is inserted beforethe dispenser is fitted with a nozzle.

EXPERIMENTAL

In the following Table I, the preferred composition of the invention isdisclosed:

TABLE I Ingredient wt. % active Buffer (NaOH) 0.0070Dispersing/emulsifying/wetting agent¹ 0.0300 Fragrance² 0.2500 CorrosionInhibitor³ 0.6000 Quaternary Ammonium Compound⁴ 0.6300 Anionic Polymer⁵1.0500 Propellant⁶ 10.0000 Water 22.4330 Ethanol 65.0000 Total 100.0000¹Byk Chemie BYK-345 ²Proprietary ³NaNO₂ ⁴Stepan BTC-885 ⁵B.F. GoodrichGA 2123 ⁶Diversified CPC Int'l A-46

The films resulting from the dispensing and curing of this formulationresulted in elegant, smooth, glassy appearing translucent films whichdemonstrated good water resistance. However, it is the disinfectancy andresidual efficacy performance which was especially noteworthy andunexpected.

In the following experiments, it should be noted that disinfectancy(contact efficacy or kill) is assessed by a 10 minute contact on asurface containing a given titer of microorganisms, whose reductionafter 10 minute contact is compared to a control. The residual efficacystudies generally are determined by repeated inoculation of a surfacewith a given microorganism, with rinsing or other removal of materialsfrom the surface between the inoculations, which are adapted fromstandard AOAC/ASTM and other protocols.

The disinfecting (contact efficacy) tests are disclosed in Tables II-Vbelow, in which the inventive formulation is tested against bacteria,viruses and fungi, respectively.

TABLE II Bacterial Disinfectancy Number of carriers Lot Number OrganismExposed Showing growth Lot #1 Staphylococcus 60.0000 1° 0 aureus 2° 0Lot #1 Salmonella 60.0000 1° 0 choleraesuis 2° 0 Pseudomonas 60.0000 1°0 aeruginosa 2° 0 Lot #2 Staphylococcus 60.0000 1° 0 aureus 2° 0Salmonella 60.0000 1° 0 choleraesuis 2° 0 Pseudomonas 60.0000 1° 0aeruginosa 2° 0 Lot #3 Staphylococcus 60.0000 1° 0 aureus 2° 0Salmonella 60.0000 1° 0 choleraesuis 2° 0 Pseudomonas 60.0000 1° 0aeruginosa 2° 0 1° = primary subculture growth; 2° = secondarysubculture growth.

The inventive composition resulted in complete inactivation of eachviral strain. The exemplary performance results are demonstrated belowin Table III.

TABLE III Virucidal Efficacy Virus Dried Virus Lot 3 Virus Lot 4 VirusCytotoxicity Cytotoxicity Reduction Virus Control Exposure Exposure Lot3 Lot 4 Titer Poliovirus 10^(6.75) ≦10^(2.5) ≦10^(2.5) ≦10^(2.5)≦10^(2.5) ≧4.25 log₁₀ type 1 Complete Inactivation Influenza 10^(4.75)≦10^(1.5) ≦10^(1.5) ≦10^(1.5) ≦10^(1.5) ≧3.25 log₁₀ Virus type CompleteA2 Inactivation HIV type 10^(6.5) ≦10^(3.5) ≦10^(3.5) ≦10^(3.5)≦10^(3.5) ≧3.0 log₁₀ 1 Complete Inactivation

TABLE IV Antifungal efficacy Visual Magnified Sample Evaluation ofEvaluation of Lot Organism Tiles Test Tiles Test Tiles Lot 3 Aspergillusniger 1-10 no growth (0%) no growth (0%) Lot 4 Aspergillus niger 1-10 nogrowth (0%) no growth (0%) Untreated Aspergillus niger 1-10 growth(75-95%) Control Tiles

TABLE V Antifungal Efficacy Number of Carriers Sample Lot OrganismExposed Showing Growth Lot 3 Tricophyton 10.0000 1° 0 metagrophytes 2° 0Lot 4 Tricophyton 10.0000 1° 0 metagrophytes 2° 0

The residual efficacy results are captured below in Tables VI-XI. TablesVI and IX show the controls in which bacterial growth are observed,Tables VII and X show the residual efficacy data, and Tables VIII and XIshow reduction calculations. In the data, “CFU” means “colony formingunits, a standard measure in microbiology.

TABLE VI Control Counts Zero Time Counts- Control Counts- Test OrganismCarrier Designation CFU/Carrier CFU/Carrier Staphylococcus aureus A 6.4× 10⁵ 1.4 × 10⁶ B 5.3 × 10⁵ Avg = 5.9 × 10⁵ 9.3 × 10⁵ Avg. 1.0 × 10⁶ C1.0 × 10⁶ Klebsiella pneumoniae A 1.4 × 10⁶ 1.3 × 10⁶ B 1.5 × 10⁶ Avg. =1.5 × 10⁶ 1.6 × 10⁶ Avg. 1.6 × 10⁶ C 2.0 × 10⁶

TABLE VII Test Substance Tile Counts Test Carrier Sample No. TestOrganism Code No. of CFU/Carrier L1-6 Staphylococcus aureus A  15 B noobservable colonies C  45 L1-6 Klebsiella pneumoniae A 690 B 135 C 660L2-1 Staphylococcus aureus A  30 B  45 C  75 L2-1 Klebsiella pneumoniaeA 195 B 195 C 135

TABLE VIII % Reduction Calculations % Reduction vs. Test Sample No. TestOrganism Carrier Code Control L1-6 Staphylococcus A 99.9 aureus B >99.9C 99.9 L1-6 Klebsiella A 99.9 pneumoniae B 99.9 C 99.9 L2-1Staphylococcus A 99.9 aureus B 99.9 C 99.9 L2-1 Klebsiella A 99.9pneumoniae B 99.9 C 99.9

TABLE IX Control Counts Control Counts- Test Organism CarrierDesignation CFU/Carrier Salmonella A 2.5 × 10⁵ choleraesuis B 1.9 × 10⁵C 4.8 × 10⁵ Escherichia coli A 6.4 × 10⁵ 0157:H7 B 5.8 × 10⁵ C 6.4 × 10⁵

TABLE X Test Substance Tile Counts Test Organism Carrier Code No. ofCFU/Carrier Salmonella A 315 choleraesuis B 450 C 195 Escherichia coli A30 0157:H7 B 30 C no observable colonies

TABLE XI % Reduction Calculations % Reduction vs. Test Organism CarrierCode Control Salmonella A 99.9 choleraesuis B 99.9 C 99.9 Escherichiacoli A 99.9 0157:H7 B 99.9 C >99.9

The foregoing data in Tables VIII and XI demonstrate generally excellentbroad spectrum residual efficacy versus both gram negative and grampositive bacteria.

The base formulation of Table I above was modified for furtherdemonstration of residual efficacy. For the sake of ease, Table XII isdepicted below with the changes made to certain reagents:

TABLE XII Additional Formulations Combination of Quaternary AmmoniumAnionic Polymer and Other Formula Compounds/Counterions changes SeeTable Quaternary Ammonium Acrylate Polymer (Carboset). 1 Compound,Chloride salt (BTC) II 25% Chloride Salt/75% Acrylate/Monoethyl ether ofSaccharinate Salt Poly(Methylvinylether/Maleic) Acid (Omnirez);Dispersing agent is alternative polysiloxane (Dow Corning 5103) III 25%Chloride Salt/75% Acrylate/Octylacrylamide Saccharinate Salt Copolymer;K₄EDTA as Chelating Agent; Dispersing Agents are Ethylene Glycol andalternative polysiloxane (Dow Corning Q2-5247)

These alternative formulations II and III were then tested for residualantimicrobial efficacy (organisms tested: Staphylococcus andKlebsiella). The results are demonstrated in Table XIII below:

TABLE XIII Residual Antimicrobial Efficacy Formula ResidualAntimicrobial Kill II 99.99% Efficacy III 99.99% Efficacy

The foregoing has described the principles, preferred embodiments andmodes of operation of the present invention. However, the inventionshould not be construed as being limited to the particular embodimentsdiscussed. Thus, the above-described embodiments should be regarded asillustrative rather than restrictive, and it should be appreciated thatvariations may be made in those embodiments by workers skilled in theart without departing from the scope of the present invention as definedby the following claims.

What is claimed is:
 1. An aerosol antimicrobial dispensable compositioncomprising: (a) about 0.01 to 15% of an anionic polymer or prepolymer,which has an acid number greater than 10 wherein the polymer may becompletely or partly neutralized by a quaternary ammonium compound, saidpolymer having a molecular weight range from 100 to 2,000,000 Daltons;(b) about 0.01 to 5% of said quaternary ammonium compound, thecomponents (a) and (b) combining to form an antimicrobially effectivecomplex; and a counterion for said quaternary ammonium compound; (c) atleast one water-soluble or dispersible organic solvent having a vaporpressure of at least 0.001 mm Hg at 25° C. and selected from the groupconsisting of C₁₋₆ alkanols, C₁₋₆ diols, C₁₋₆ alkyl ethers of alkyleneglycols and polyalkylene glycols, and mixtures thereof, said at leastone organic solvent being at least 20% of the composition; (d) about 1%to 50% of a propellant; and (e) less than 70% water.
 2. The dispensablecomposition of claim 1 wherein said counterion is selected from thegroup consisting of halides, hydroxides, saccharinates, carbonates,phosphates, phosphonates, sulfates, bisulfates, alkylsulfates,carboxylates, other negatively charged counterions, and mixturesthereof.
 3. The dispensable composition of claim 2 wherein said halidesincludes chlorides, bromides and iodides.
 4. The dispensable compositionof claim 3 wherein said counterion is a chloride.
 5. The dispensablecomposition of claim 2 wherein said counterion is a saccharinate.
 6. Thedispensable composition of claim 3 wherein said counterion is acombination of a chloride and a saccharinate.
 7. A method for treating asurface containing microorganisms, or which could contain saidmicroorganisms thereafter, said method comprising the steps of: (i)delivering an admixture via a propellant, wherein the admixture andpropellant are derived from an aerosol composition comprising: (a) about0.01 to 15% of an anionic polymer or prepolymer, which has an acidnumber greater than 10 wherein the polymer may be completely or partlyneutralized by a quaternary ammonium compound, said polymer having amolecular weight range from 100 to 2,000,000 Daltons; (b) about 0.01 to5% of said quaternary ammonium compound, the components (a) and (b)combining to form an antimicrobially effective complex; and a counterionfor said quaternary ammonium compound; (c) at least one water-soluble ordispersible organic solvent having a vapor pressure of at least 0.001 mmHg at 25° C. and selected from the group consisting of C₁₋₆ alkanols,C₁₋₆ diols, C₁₋₆ alkyl ethers of alkylene glycols and polyalkyleneglycols, and mixtures thereof, said at least one organic solvent beingat least 20% of the composition; (d) about 1% to 50% of a propellant;and (e) less than 70% water; and (ii) applying said admixture to asurface.
 8. A device for dispensing an aerosol antimicrobial compositionwhich comprises: a closed container containing said composition, saidcomposition comprising: (a) about 0.01 to 15% of an anionic polymer orprepolymer, which has an acid number greater than 10 wherein the polymermay be completely or partly neutralized by a quaternary ammoniumcompound, said polymer having a molecular weight range from 100 to2,000,000 Daltons; (b) about 0.01 to 5% of said quaternary ammoniumcompound, the components (a) and (b) combining to form anantimicrobially effective complex; and a counterion for said quaternaryammonium compound; (c) at least one water-soluble or dispersible organicsolvent having a vapor pressure of at least 0.001 mm Hg at 25° C. andselected from the group consisting of C₁₋₆ alkanols, C₁₋₆ diols, C₁₋₆alkyl-ethers of alkylene glycols and polyalkylene glycols, and mixturesthereof, said at least one organic solvent being at least 20% of thecomposition; (d) about 1% to 50% of a propellant; and (e) less than 70%water.
 9. A film or residue on a surface from the application of adispensable antimicrobial composition to said surface, said aerosolcomposition comprising: (a) about 0.01 to 15% of an anionic polymer orprepolymer, which has an acid number greater than 10 wherein the polymermay be completely or partly neutralized by a quaternary ammoniumcompound, said polymer having a molecular weight range from 100 to2,000,000 Daltons; (b) about 0.01 to 5% of said quaternary ammoniumcompound, the components (a) and (b) combining to form anantimicrobially effective complex; and a counterion for said quaternaryammonium compound; (c) at least one water-soluble or dispersible organicsolvent having a vapor pressure of at least 0.001 mm Hg at 25° C. andselected from the group consisting of C₁₋₆ alkanols, C₁₋₆ diols, C₁₋₆alkyl ethers of alkylene glycols and polyalkylene glycols, and mixturesthereof, said at least one organic solvent being at least 20% of thecomposition; (d) about 1% to 50% of a propellant; and (e) less than 70%water.